Kaohsiung, April 25 (CNA) CPC Corp. Taiwan, the country's biggest oil refiner, will be fined NT$400,000 (US$13,212) after its naphtha cracking plant polluted the air on Friday afternoon when the facility's uninterrupted power supply tripped, a Kaohsiung official said. The electrical short resulted in a system failure that caused heavy black smoke to be emitted up one of the Fifth Naphtha Cracking Plant's flares used to combust hazardous gases, said Hsu Ju-kai, head of CPC's Kaohsiung complex. Firemen were called to the scene and had the situation under control within 30 minutes after arriving at the factory, the local fire department said. Officials from Kaohsiung's Environmental Protection Bureau were also there collecting samples of the air, and Chang Jui-hui, the bureau's chief secretary, said toxic alkanes and alkenes were later found among the samples. The bureau will fine the company NT$400,000 because it was the second time CPC was found guilty of an air pollution violation in the past 12 months, Chang said. (By Wang Shwu-fen, Chang Che-fon and Kay Liu)